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ROT13 Cipher
Apply ROT13 substitution cipher
By Craftisle Team
About ROT13 Cipher — Free Online Tool
Apply the ROT13 cipher — a simple substitution cipher that replaces each letter with the 13th letter after it in the alphabet. ROT13 is its own inverse, so applying it twice restores the original text.
How to Use ROT13 Cipher — Step by Step
- Enter text
Type or paste the text you want to encode/decode.
- Apply ROT13
Click Apply ROT13. Since ROT13 is its own inverse, the same button encodes and decodes.
Use Cases for ROT13 Cipher
Obscuring text
Lightly obfuscate text in forum posts or code comments (not secure encryption).
Learning cryptography
Understand how substitution ciphers work as a first step into cryptography.
Puzzle solving
Decode ROT13-encoded puzzles and riddles.
FAQ — ROT13 Cipher Free Online Tool
Is ROT13 secure?
No. ROT13 is not encryption — it's a simple substitution cipher that can be broken instantly. It's only for fun/obfuscation, not security.
Why is ROT13 its own inverse?
Because there are 26 letters in the English alphabet. Rotating by 13 twice gives 26, which wraps around to the original letter.